Ancient trees
A tree is ancient when it is in its last third of its natural life looking old and gnarled in appearance and often showing signs of heart rot and dead boughs.

Ancient woodland
Woodland proven to exist since 1600AD, when maps first became common. Trees may have been felled and have regrown on the same site. Presence of '‘indicator plant species' also provides evidence.

Biodiversity
Life in all its various forms together with the complex relationships between them.

Ecological Community
A specific group of plants and animals inhabiting the same area and interacting with each other.

Biological Diversity Convention
International agreement focusing on biodiversity and signed by the Prime Minister and 150 others Heads of State or Governments at the Rio de Janeiro Earth Summit in June 1992.

Corridors
The term given for a network of land in which species can thrive or disperse. They connect otherwise isolated areas of habitat where populations are well established.

Countryside & Rights of Way Act 2000
Law incorporating Biodiversity, SSSIs, ADNBs, Rights of Way.

EC Habitats & Species Directive 1992
This requires Member States to take measures to maintain or restore natural habitats and wild species at a favourable conservation status in the Community.

Flagship Species
Species that are typical and indicate a high quality habitat. Also includes those species associated with the particular habitat that are rare, scarce or particularly important.

Fragmentation
The subdivision of habitats so threatening the viability of populations.

Habitat
A habitat is a place in which a particular plant or animal lives. Often used in a wider sense, referring to major assemblages of plants and animals found together.

Hedgerow Regulations 1997
Important hedgerows are assessed according to the criteria listed in the Regulations.

Improved
A process by which the agricultural quality of land is made better for the growth of agricultural crops or pastoral grasses by the application of fertilisers, pesticides and alteration of soil texture eg. ploughing.

Landscape assessment
The description, analysis and evaluation of landscape within defined objectives in order to derive its character. Studies are often undertaken with a view to formulating recommendations for long-term management strategy of each landscape character area identified.

Meta-population
A cluster of small communities of a particular species which have the potential to mix and can together form a viable population for breeding.

National Vegetation Classification
Methodology which enables British plant communities to be classified.

Negative indicators
Features or species that show the extent to which a habitat has been altered.

Objective
The means by which an aim can be achieved.

Phase I
A standardised system for classifying and mapping wildlife habitats in all parts of Great Britain, including urban areas.

Phase II
A standardised system for undertaking a detailed analysis of plant communities within a habitat and may also include surveys of animal species.

Rare
Nationally rare species are those, which occur in 15 or fewer 10x10km squares of the national grid.

Retrievables
Species, which have undergone such a decline that, they are no longer apparent on a site but may recover to expected levels.

Ruderal
A plant that grows on disturbed ground, having good colonising powers, often annual or biennial and will be out-competed over time.

Scarce
Nationally scarce species are those, which occur in 16-100 10x10 km squares of the national grid.

Secondary Woodland
Woodland growing on a site that has been cleared at some time.

Semi-natural
Closely resembling the natural vegetation of an area, modified by human activity, but having communities of naturally occurring native species.

Site of Importance for Nature Conservation (SINC)
Areas designated by the Greater London Authority on account of their local wildlife value.

Site of Special Scientific Interest (SSSI)
Nationally important sites designated by English Nature on account of their wildlife (or geological) value. Protected under the Wildlife & Countryside Act 1981.

Sustainable Development
Development, which meets the needs of the present without compromising the ability of future generations to meet their own, needs.

Target
A fixed goal or objective at which action is directed to achieve a desired state.

Tree Preservation Order
Order made by a local planning authority which in general makes it an offence to cut down, top, lop, uproot, wilfully damage or wilfully destroy a tree or group of trees without the planning authority's permission.

Unimproved
Vegetation that resembles that which is typical for a particular habitat type.

Wildlife & Countryside Act 1981
Law incorporating Species and SSSI protection.